A US survey found that about 20% of young people aged 11 to 19 had experienced cyber-bullying in 2004The internet has become a dangerous place for teenagers now that bullies use it to harass people online

Cyber-bullying can kill. But what's most shocking is that it emerged last week that the teenager who drove a 13-year-old girl to hang herself a year ago in Missouri, US, was actually an adult.

The tragedy captured global attention after it was revealed in a local newspaper that a cruel hoax by an adult drove Megan Meier to commit suicide.

The sad story began when Meier, who suffered depression and low self-esteem, met a handsome boy called Josh at the MySpace website. The two quickly developed an online synergy lasting more than a month before Josh ended the correspondence, saying that he heard bad things about Meier.

It emerged that Josh's account had been used to post insulting messages like 'She is fat' or 'She is a slut' on other internet message boards. The last communication Meier received from him said: 'The world is better without you.' Hours later, her parents found her hanging dead in her room.

But the bizarre twist in the tale is that Josh never even existed. He was, in fact, a hoax identity. Worse still, Josh was fabricated by adults - Meier had fallen out with a friend at school and adult members of that friend's family dreamed up and acted out the deadly deception. Meier was only one of many victims of cyber-bullying - the online style of the old-fashioned school version. This Web-based phenomenon has escalated in recent years because of immensely popular socialising websites like MySpace and instance messaging software.

A survey published recently in the US found that about 20 per cent of 770 young people interviewed aged 11 to 19 had experienced cyber-bullying in some form or other during 2004. Ten per cent complained that photos taken by cellular phone cameras were posted without consent.

The anonymous nature of these internet postings seems to drive the bullies to new levels of cruelty. There are children launching online polls on the 10 ugliest or fattest girls in a class. To rub salt into wound, the results are sent to the girls concerned. The technology makes it very easy and they have no idea how their behaviour can devastate those targeted.

For victims the attention seems inescapable - there's no place to hide when they are in front of the computer reading nasty comments about themselves.

In Japan, this aggression has developed into a new technological form - mobile phone bullying. Victims receive harassing phone calls and messages from bullies all the time through their mobiles.

Meier was not alone - there have been cases of victims attempting to suicide worldwide. The technology used means that parents and teachers are often kept in the dark and have no idea what pain their children are going through.

Victims are too ashamed to complain to adults. Teachers are unlikely to spot the harassment at school because cyber-bullying is almost undetectable unless parents access the websites involved.

The logical solution would be to deny students access to computers and phones but most children and teenagers would rather keep quiet than face the possibility of losing internet access.

Yet in the Meier case the problem has broken new ground - with adults involved. Many would say to strategically harass, with or without physical contact, a teenage girl and drive her to suicide constitutes child abuse. Yet there is no law addressing cyber-bullying. The rapid rate of technological development far exceeds the creation of new laws, but the Meier case has prompted calls for action. There is an anti-cyber-bullying campaign gaining momentum. You Tube has set up the Beatbullying You Tube Channel to enable young people to fight back.

The best way to combat cyber-bullying is to ignore them. Save the messages or pictures as evidence and contact parents, police or teachers for help.

This problem does not lie in technology - it's the people who need to take responsibility.